The Open Question Argument
G E Moore put forward this argument as a means of attacking naturalistic moral theories
– theories which claim that moral properties are identical with some natural property in
the world such as pleasure.
The argument basically runs as follows:
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If something is identical with something else, then this is obvious to
competent speakers of the language. For example, it is obvious to us that
pentagons are identical with five sided shapes which have five interior
angles.
If the identity between the two things is obvious, then a question which asks
if the two things are identical will have an obvious answer of yes – this is a
‘closed question’.
When we ask, ‘Is pleasure good?’, the answer is not obvious, so this is an
‘open question’.
If it is an open question, then it cannot be the case that pleasure is good,
because this would be a closed question.
All attempts to identify moral properties with natural properties generate
open questions.
So moral properties are not natural properties.
Here are two possible responses to Moore.
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The Analogy with Rules of Grammar
Decide if the following question is open or closed:
Is it grammatically correct to say ‘Were you to be late, I would be angry’?
One can be a competent user of the language and find this to be a genuinely open
question. This is because we use the rules of grammar without a full, conscious
awareness of what they all are. Why could it not be the same in ethics? Could it not be
that we act in ways which indicate that we identify goodness with pleasure, but it is not
obvious to us when asked if this is what we are doing.
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Identity and Language
Must we think that a relation of identity is obvious in language? Could there not be an
‘open question’ when there is a relation of identity but we are just not clear about it?
Let us say someone asks the question, ‘Is all water H2O?’ A competent user of the
language may believe this is an open question even though water is identical with H2O.
This suggests that Moore is mistaken in thinking that an open question rules out the
possibility of an identity between natural and moral properties – it may simply be a
problem of understanding how meaning is created.